When AIPAC convened in 2009, speakers and attendees had cautious hope about how the new administration would stand up to challenges ranging from the Middle East peace process to Iran and its nuclear ambitions.

This time around, the mood is less optimistic and more critical of the administration’s first year.

“There’s no time to lose [on stopping Iran],” Roz Rothstein, international director of the pro-Israel advocacy organization StandWithUs, told The Hill. “This administration is acting like it’s got a lot of time.”

U.N. Watch Executive Director Hillel Neuer similarly criticized U.S. inaction at the newly joined Human Rights Council in the face of opposition crackdowns by Tehran. “None of the members of the council, including the United States, has even tried to introduce a resolution on Iran,” Neuer told The Hill.

Harsh U.S. criticism earlier this month of the new housing plan in Jerusalem has exacerbated tensions, which Clinton sought to soothe in her address.

The secretary of State said the move “exposes daylight between Israel and the United States that others in the region hope to exploit.”

“We objected to this announcement because we are committed to Israel and its security,” she said. “Because we do not want to see the progress that has been made in any way endangered.”

Clinton got a chillier reception than the one offered to Biden last year.

She received light applause at parts of her speech, such as when she condemned the recent ceremony in which the Palestinian government named a square in Ramallah after Dalal Mughrabi, a Fatah woman who in 1978 led an operation in which 37 Israeli civilians and an American photographer were killed.

In contrast, Sen. Evan Bayh (D-Ind.) received a standing ovation Sunday for likewise condemning the honor.

Clinton, in reference to both that incident and the tiff with Israel over settlements, said parties should “refrain from unilateral statements and actions that undermine the process or prejudice the outcome of talks.”

Sherman, alluding to the settlement crisis, said he could only imagine how the White House will react if Israel takes disarming Iran into its own hands by striking Iran’s nuclear facilities in the next 18 to 24 months.

“If you think a little flap about 1,600 housing units is a little public-relations issue, you ain’t seen nothing yet,” Sherman said.

The crowd was noticeably quiet during another part of Clinton’s speech when she compared the peace process to the story of Jews following Moses into the Promised Land despite their trepidation.

“This generation of Israelis must also take up the tradition and do what seems too dangerous, too hard and too risky,” she said.

Obama, who has not yet visited Israel as president, was invited to speak at this year’s conference but cited a scheduling conflict with his trip to Indonesia — a trip later postponed twice to shepherd through the healthcare bill.

Overall, the administration line laid out at AIPAC was clear: press forward with sanctions and efforts at diplomatic engagement with Iran, press for a two-state solution beginning with proximity talks, and hold the line with Israel on new settlement-building.

Bayh earned a warm reception Sunday when he said the White House needs to consider the use of force against Iran to keep the country from getting nuclear weapons.

“We need to go forward with aggressive sanctions that are likely to hurt the regime ... but that’s unlikely to work,” Bayh said. “In the long run, you have to do what you have to do.”

Outside the plenary hall, Bayh was greeted by conference attendees who mugged for photos with the first lawmaker to address the conference. The senator patted on the shoulder and thanked one man who told Bayh he should run for the Oval Office.

“I don’t know what my future will involve,” Bayh told The Hill. “But I’ve had a great relationship with AIPAC and that will continue. I do plan on continuing to come to conferences like this.”

This year’s AIPAC conference kicked off on the day of a landmark victory for Democrats with the passage of the healthcare reform bill, and conference attendees clearly saw an opening for lobbying for a shift in legislative priorities.

Alexander Chester, a Harvard Law student who led a student group lobbying Harvard alumni (of which there are 38 in Congress) to sign onto a statement urging Iran divestment, said that while the healthcare bill was in flux, it was more difficult to get a commitment from preoccupied members.

Now Chester is hoping to bend the ear of congressional leaders to join supporters such as Rep. Barney Frank (D-Mass.) in turning from healthcare to Iran. “Hopefully they can go from one success to another,” he said.